This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 3 |
| 3 | -12 |
| 4 | 93 |
| 5 | -852 |
| 6 | 9543 |
| 7 | -125592 |
| 8 | 1901433 |
| 9 | -32557992 |
| 10 | 622171083 |
| 11 | -13127139492 |
| 12 | 303107003733 |
| 13 | -7602746576892 |
| 14 | 205855300099983 |
| 15 | -5984428053529392 |
| 16 | 185914355908981233 |
| 17 | -6146745514853869392 |
| 18 | 215496349961845902483 |
| 19 | -7985298182676045656892 |